Medical research keeps unravelling the most unexpected results that are baffling to say the least. Potatoes, which have always been considered safe and healthy, have been found to raise blood pressure if consumed more than four times a week. Surprisingly mashed, boiled, or baked potatoes are nearly as likely to raise blood pressure as chips, the research reveals.
Researchers from the Harvard Medical School said they suspected that the starch in potatoes was to blame. Because potatoes have a high glycaemic index these starchy carbohydrates rapidly transform into sugars in the body, triggering a sharp rise in blood sugar levels.
In the long term this may cause blood sugar problems, exacerbating diabetes. The experts, whose work was published recently in the British Medical Journal analysed data from 187,000 men and women tracked in three large US projects for 20 years. The results suggest that women who regularly eat potatoes may be at slightly higher risk of blood pressure than men.
Overall, however, they found that men and women who ate four or more servings of baked, boiled or mashed potatoes a week had an 11% increased risk of high blood pressure compared to those who ate potatoes less than once a month. Those who ate chips four or more times a week had a 17% higher risk of high blood pressure.
Replacing one serving a day of potatoes with one serving of non-starchy vegetables led to a 7% drop in the risk of high blood pressure, they found. Eating crisps had no effect the experts discovered. The researchers said that potatoes should no longer be included as vegetables when the government issued health advice, just as they aren’t in the UK.
Victoria Taylor, senior dietician at the British Heart Foundation, said: ‘This type of study can only show an association, not cause and effect. Although a higher consumption of potatoes such as mashed potatoes or French fries, was associated with high blood pressure, it is still possible that other factors in the diet or lifestyle are also affecting the results.’ She added: ‘In the UK white potatoes are not included in the five a day recommendations for fruit and vegetable consumption.
‘Nearly 30% of adults in the UK have high blood pressure, so it is key that we understand the condition and its causes.’
Professor Tom Sanders of King’s College London said: ‘Being overweight, a high intake of salt and alcohol, and a low intake of potassium are all known to increase blood pressure, but the effects of individual foods are less certain.
‘Generally, fruit and vegetables are associated with low blood pressure, with the exception of pickled vegetables. However, potatoes – especially chips – are often consumed with added salt which may be part of the explanation for this association with raised blood pressure.
‘I don’t think this study should be used to discourage people from eating potatoes. In the UK potatoes are more widely consumed than in the US and make an important contribution to the intake of Vitamin C and potassium.’
Now you have been told. Food in general taken in small quantities is, in my view, the key to a healthy diet and the less you eat in the evening, the better sleep you get and the more fit you become. Obesity and gourmandise are the scourge of it all.